1. Field of the Invention
The present invention relates to purified plant extracts effective against peptic ulcer, and particularly to a Convolvulus extract for the treatment of peptic ulcer and Helicobacter pylori infection that is an extract of Convolvulus pilosellifolius, and to the active ingredient isolated from the extract.
2. Description of the Related Art
The family Convolvulaceae contains a large number of plants. The largest genus is Convolvulus, which comprises about 250 species of flowering plants, including trees, shrubs and herbs. Common names include bindweed and morning glory, both names shared with other closely related genera. They are annual or perennial herbaceous vines, bines and a few species of woody shrubs that grow from 0.3 to 3 meters tall. The leaves are spirally arranged and the flowers trumpet-shaped, mostly white or pink, but may occur as blue, violet, purple or yellow in some species. Convolvulus pilosellifolius, a species of Convolvulus, is commonly known as soft bindweed. Most of the Convolvulus plants contain alkaloids, flavonoids and coumarins. In addition, they possess many pharmacological properties, including cytotoxic, antioxidant, anti-inflammatory and antiulcer activities. Some Convolvulus plants are used in traditional medicine (TM) for the treatment of coughs and asthma.
Peptic ulcer is a common gastrointestinal disorder in the modern era, and it is a global health problem affecting a large number of people worldwide. Helicobacter pylorus is recognized as a major etiologic agent in gastrodudenal diseases, including chronic gastritis, peptic ulcers, gastric adenocarcinoma and mucosa-associated lymphoid tissue lymphoma. The current treatment regimens for H. pylori infections are based on the combination of a proton pump inhibitor and two antibiotics (triple therapy). There are different classes of drugs that have been used in the treatment of peptic ulcer. Most of them, however, exhibit serious side effects, such as arrhythmias, gynaecomastia, arthralgia and hypergastrinemia. Additionally, the use of antibiotics leads to increasing development of bacterial resistance that has compromised the efficacy of this method of treatment.
Increasing antibiotic resistance in clinical isolates of bacteria, including H. pylori, strongly support the search for new and safe antibacterial compounds from native medicinal plants. In this regard, many species of plant and their derivatives, including isolated compounds and extracts of the lichen Certaria islandica, Chinese green tea and several native plants used in folk medicine for the relief of gastric symptoms have been studied to establish their pharmacological activity. In fact, a number of drugs and natural substances, such as various essential oils, extracts of the lichen Certaria islandica, Chinese green tea and several native Iranian plants have been shown to have in vitro antibacterial activity against H. pylori. There are also some published studies on the activity of a number of plant extracts against Helicobacter pylori. 
Therefore, in the discovery of new anti-ulcerogenic drugs, special interest has been directed to natural plant products based upon traditional medicine (TM). Therapies based on natural products (plants & herbs) derived from TM have proved to be clinically effective and relatively less toxic than the existing pharmaceutical drugs because it reduces the offensive side effects of pharmaceutical drugs, especially those caused by Helicobacter pylori. Accordingly, the search for new effective therapeutic agents is of paramount importance to find more effective natural product, pure extracts and active compounds derived from TM that are effective against ulcer activity caused by Helicobacter pylori. 
Thus, a Convolvulus extract for treating peptic ulcer and Helicobacter pylori infection solving the aforementioned problems is desired.